Process of making cementitious material of cellular structure



I06. COMPOSITIONS,

COATING OR PLASTIC.

UNITED STATES PATENT OFFICE.

GEORGE B. HINTON, OI MEXICO, MEXICO.

PROCESS OF MAKING CEMENTITIOUS MATERIAL OF CELLULAR STRUCTURE.

30 Drawing. Application filed September 19, 1927. Serial No. 220,843.

preferably with this proportion of water that has been already saturatedwith cement. A small quantity of a flotation oil is added. This cementpulp ismd by agitation for a short time and then put into the flotationapparatus.

Any reagent known in commerce as flotation oil will give a result, butsome of these flotation oils give better results than others. Of theflotation reagents that have been tried the following give the bestresults:

Pine oil especially when mixed with a eavy collecting oil such aspetroleum or coal tar.

Phospo-cresylic acid (aerofloat reagent).

Oleic acid (red oil).

Sodium res1nate. (d 4.

The total quantity of oil or mixture of oil does not exceed 0.2 of thedry weight of the whit-T! s The term flotation oil, including collectingoils and frothing oils, is well known in the art of metallurgy whereoils are used in the flotation process for separating minerals fromtheir ores. \Vhereas the oils used in the flotation process embrace manyreagents of different chemical nature, yet their common property ofinducing the attachment of a film of air to a grain of a solid, bringsthem together under the classification of flotation oils.

This process for the manufacture of a cementitious material of acellular texture resembles the flotation process in that an oil is usedto form a froth. The action of oil in forming a froth is the basicreaction of the flotation process as developed in the art of separatingminerals from their ores.

The basic reaction of the flotation process consists in the attachmentof a bubble of air to a grain of a solid by means of a film of oil. Thesimple phenomenon is that the oil sticks to the solid and the air sticksto the oil; therefore, if a minute quantity of oil be added to a pulp ofwater and ground solid and the whole be aerated and agitated, the rainsof solid will be coated with a film of 011 and to this film of oilbubbles of air will be attached or adsorbed, and grains of Thisinvention relates to a process for making a cementitious material ofcellular texture, by introducing air by agitation or other means into apulp of hydraulic cement and water to which has been added a smallquantity of a frothing flotation reagent. This application is a;continuation in part of my application Serial No. 165,494, filed Feb.2,1927.

The material made in accordance with the present invention isessentially a form of concrete of cellular texture, that is impermeableto the passage of liquids. The process resembles the flotation processknown in the art of separating minerals, in that a certain kind of oil,called a flotation oil, is used to induce the adherence of a film of airto a grain of a solid, but the present invention is different from theflotation process in that I use the properties of a flotation oil not toseparate minerals but to coat bubbles of air with cement.

Air, cement, and water will not mix together. If a cement pulp be beatenup with air, most of the air will separate from the pulp as soon as thebeating stops. But if a cement )ulp be beaten u with air and a W0 a:" flo ta t 1 on oil; an extraordinary change takes place The bubbleformation is accelerated and stabilized. Air is found to be completelymiscible with cement pulp in the presence of a minute quantity of aflotation oil. This is my discovery and the use of this principle tomake cementitious materials of cellular texture is the subject of thispatent application. My meaning of the term flotation oil will behereinafter defined exactly.

The proportion of air to cement in my product depends largely upon theproportion of water to cement in the cement pulp or grout with which theflotation oil is agitated. Cement grouts with less than 30% water byweight are unworkable. Grouts with over of water by weight producecementitious materials of too light weight to be generally useful. I

For carrying out the rocess I find that a mechanically operated otationmachine for separating minerals from their ores may be use In theoperation of the process cement is mixed with from 30% to 60% of wateror encloses each bubble of air. The reagents referred to herein asflotation oils are those that when used as described, result in theExamin solid will be embedded in the film of oil that basic reaction ofthe flotation process as set forth above.

These reagents well known in the art as flotation oils belong chiefly tothe following 5 chemical groups:

Coal tar and petroleum and derivatives of these.

The oily products of the distillation of ve etable matter.

ily organic acids.

A froth produced by the basic reaction of the flotation process asdescribed has characteristics that differentiate it from froths made bother than this reaction.

1 The otation reaction requires only a very small quantity of flotationoil to make 'a. froth, less than 0.2% of the dry weight of the solid.

The flotation reaction is a molecular surface tension reaction betweenthe oil, water,

air and solid.

The durability of a flotation froth of cement does not depend in any wayon the mechanical strength or stickiness of the oil,

for with a given minimum quantity of flotation oil sufficient to filmthe grains of cement the mechanical properties of the froth areindependent of the quantity of oil added within wide limits.

The adherence of the reagent to a particle of solid matter and of theair to the reagent is a molecular surface tension reaction. Under theseconditions, the minute bubbles of air coalesce under the influence ofsurface 3 tension and each bubble of air will be enclosed in the film inwhich are embedded the grains of the solid material. Thus it will beseen that the presence of a flotation reagent in an aerated cement pulpproduces cement coated bubbles of air. The stability of a froth ofcement produced by the flotation process is attributable to theinter-reaction of the air, water, oil and cement.

In order to reduce the cost of the product,

a filler such as sand or other inert material may be added 0 e cementpulp.

Having set forth a preferred embodiment of my invention, I claim:

1. The process of making a cementitious material which comprises forminga pulp of hydraulic cement, water and a frothing flotation reagent, andagitating the pulp to a froth. 1

2. The process of making a cementitious material which comprisesaerating a pulp composed of hydraulic cement, water and a relativelysmall amount of a frothing flotation reagent to produce a relativelystable froth.

3. The process of making a cementitious material of cellular structurewhich comprises preparing a mixture of hydraulic cement and water,adding thereto a relatively small quantity of a frothing flotationreagent, and agitating and aerating the pulp to a frothy consistency.

4. The process of making a cementitious material which comprises forminga pulp of hydraulic cement, water, inert filler and a frothing flotationreagent, and agitating the pulp to a froth.

5. The process of making a cementitious material which comprisespreparing a mixture of hydraulic cement, water, and an inert filler,adding thereto a relatively small quantity of a frothing flotationreagent, and agitating and aerating the pulp to a frothy consistency.

Signed at Mexico, D. F., this tenth day of September, 1927.

GEO. B. HINTON.

DISCLAIMER.

1,6 57.716.George B. Hinton. Mexico, Mexico. PROCESS OF MAKINGCEMENTITIOUB MATERIAL or CELLULAR Srnocroms. Patent dated January 31,1928. Disclaimer filed August 1. 1928, by the patentee.

-Hereby enters this disclaimer to that part of the specification whichis in the following words, to wit: sodium resinate occurring 1n line 70of page 1 of the specification.

[O ficial Gazette August 21, 1.928.]

. MUM m mun-An.

